1. Field of the Invention
A foam-formed nonlaminated stratified paper tissue includes a first zone of foam-formed paper tissue formed from a furnish of hardwood kraft. A second zone of foam-formed paper tissue is formed from a furnish of softwood kraft. The second zone is formed unitary and entangled with the first zone to form a nonlaminated stratified paper tissue having a high softness integument on an outer surface of said first zone which is an enriched region having a substantial purity of hardwood kraft. The enriched region provides an extremely soft and smooth surface detectable by human somatic sensibility.
2. Description of Background Art
Hithertofore, paper tissues have been constructed and formed by utilizing a water-forming process wherein fiber blend is suspended in a liquid solution and delivered from a headbox onto a twin wire, Fourdrinier, suction breast roll former or crescent former machine. The water-formed tissue may be produced to include one or more layers formed by multiple headboxes. In addition, a headbox may be utilized having a single slice outlet or a plurality of slice outlets depending on the number of regions in the product desired to be produced. The water-formed tissues which are formed as a multilayer product by means of multiple headboxes tend to delaminate. Delamination is a phenomena whereby individual regions may be separated one from another, the interface between the regions is not so highly entangled as to prevent the separation of the various regions in a multilayer water-formed tissue.
Further, in a water-formed process, the furnish which is supplied to the headbox includes typically 0.15% by weight of fibers. If a two-slice outlet is provided in the headbox, two distinct furnishes may be supplied to each portion of the headbox so as to form regions which are predominantly composed of the fibers of the particular furnish which is supplied to the separate sections of the headbox. For example, a softwood kraft may be supplied to one portion of the headbox. Softwood kraft is produced from wood fibers which are relatively long in length. The second section of the headbox may be supplied with a 0.15% furnish of hardwood kraft. Hardwood kraft is formed from wood fibers having fiber lengths which are relatively short.
In a conventional water-formed papermaking process, approximately 50% to 60% of the furnish which is supplied to a Yankee tissue machine is retained on the wire. In other words, approximately 40% to 50% of the furnish supplied to the wire is actually recycled back into the furnish which is eventually supplied to the two sections of the headbox. The fibers which are not retained on the wire are recirculated through a collection pit back into the supply line for the headbox which contains the 0.15% by weight of fibers. Pure 3% softwood kraft supply pulp or the 3% hardwood kraft supply pulp is also supplied to the supply line for the appropriate headbox to be mixed in to form the 0.15% furnish. Since 40% to 50% of the material supplied to either the softwood kraft or the hardwood kraft is a mixture of long papermaking fibers or short papermaking fibers which are drained from the wire as the furnish is deposited thereon, the purity of the softwood kraft and the hardwood kraft as it is supplied to the two sections of the headbox is diluted. For example, if over 50% of the fines are not retained on the wire, these undesirable fines would be recirculated back into the softwood kraft pulp and the hardwood kraft pulp for eventual supply to the two sections of the headbox and the softwood kraft and the hardwood kraft would only be provided with new material to the flow lines for the headbox as the system reaches equilibrium state. Thus, the material in each section of the headbox is not pure.